Metallurgical process.



PATENTED MAR. 13, 19706.

F. T. SNYDER. METALLURGICAL PROCESS.

APPLICATION FILED JUNE 23, 1905- @W mbmp I v the ores to oxids and then reducing the roasted ore with crushed carbon in a retort by containing any considerable amount of slagthe retort. This is particularly true' of a passa e of heat to the contents, and so are 7 metal in a free state and fo carbon bisulfid by the reactioh of uni ig electrode and carbon bis .tions the zinc oxid is reduced and the metal is mixed with carbon and with S1 FREDERICK T. SNYDER, or OAK PARK, ILLINOIS.

Specification of Letters Patent.

METALLURGICAL sRocEss'.

Patented March 13, 1906.

Application filed June 23, 1905. Serial No. 266,640.

To all whom it may concern:

Be it known that I, FREDERICK T. SNYDER, a citizen of the United States, residing at Oak Park, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Metallurgical Processes, of which the following is a full, clear, concise, and exact description.

My invention relates to a process of treating sulfid ores for the extraction of the metal in a simple, direct, and economical way, and involves also the formation of 'a sulfur-bearingrcompound as a by-product.

he present commercial method of reducing zinc sulfid ores involves first roasting means of external heat, air bein excluded from the retort. Under favora le condi-' liberated in the form of va or, which is afterward collected and con ensed. Zinc ores forminfimaterials, however, cannotb'e commercia y treated in this way, because the slag corrodes and eats through the walls of basic slag containing lime with iron, which takes up silica from theretort. The walls of the retort are necessarily thin to'permit the soon estroed by the slag. ,Such ores can not-be sme ted in a blast-furnace, because the zinc if reduced is immediately burned ain to oxid by the blast.

n accordance with my invention the roasting may be dispensed w1th, and the sulfifd ore ormmg materialand the mixture smelte upon a bath of molten slag in an electric furnace from which air is excluded, whereby the metallic sulfid is broken down, liberating the g and carbon. Preferablythe electric current is passed directl throughmthe body of molten 'sl in the ace, in which a portion 2% bon will be augmented by the electrol ic action of the current u n the materia in the fused bath,the metal liberated atone d being formed at. theiother' electrode b the nascent sulfur combining :with the car 11.

Inthe treatment of zinc-sulfid are as abov,e

' described the zinc is liberated in the form of vapor at the high temperature employed about 1,000 or 1,200 centigradeand may be collected and condensed apart from the carbon bisulfid. The condensation of the zinc-vapor also serves to separate it from an carbon bisulfid with which it ma be dilute because the latter will not con ense except at a much lower temperature. As a result of electrolysis, however, the formation of carbon bisulfid will naturally take place at the anode by the combination of the nascent sulfur with the carbon, while the zinc-vapor will be liberated at the cathode, so that the .two gases may be kept separate bysuitable partitions in the furnace. In such case the zinc-vapor, being unaccompanied by any appreciative amount of diluting-gases, may be condensed in liquid form.

The success of this process has been experimentally demonstrated in the following manner: An electric furnace provided with carbon electrodes and closed to the air during operation was started by; heaping scrap lead between the electrodes arid melting down the lead by the p'assa e of ad electric current to form a fused bat Sla -forming material consisting of the ore to be treated (in this case a zinc-blende) mixed with iron and lime as fluxes was then fed into the furnace and melted down to form a fused bath 'of slag, most of the lead being then tapped off and the operation continued by passing a-current through the slag. B means of a current of fifteen hundred or ei liteen hundred amperes atan electromotive orce ranging from seven to fifteen volts .the furnace was heated to about 1,200 centigrade, and under such conditions the ore was reduced, metallic zinc being liberated in the form of vapor'near one electrode, while carbon bisulfid .was formed near the other electrode. It is diflicult to say to what extent the reduction of the sulfid is due to the electrolytic effect of the current as distinguished from the reducing action of hightemglerature employed,

the carbon at the but electrolysis un oubte y takes place, and I thereforeprefer to em loy direct instead of alternating current. e orein uestion', as before stated was a zinc sulfid an contained approximately twenty 7 per cent. of zinc, twenty r cent. of iron, five r cent. of lead, thirty-fite per cent. of s ur, and twenty per cent. of earthsisilica and alumina.

In the ordinary method of zinc distillation with retorts, as previously described, only not be melted down to form a slag. As before mentioned, the production of-a slag Would cause the destruction of the retort. In my rocess of reduction, on the other hand, the

ormation of slag is an essential feature, the materials of the charge being thoroughly melted down in a liquid or semiliquid state, so'that in the presence of an excess of carbon the reduction of the zinc is very thorough, and the temperature is maintained at so hi h ad'egree that the reduced zinc is thoroug y boiled out of the slag and recovered. It is entirely possible by my process to recover ninety-four per cent. or more of the amount of zinc in the charge. Furthermore, it is not necessary in my process to roast the ore, although 1t should be understood in treating zinc ores that the presence of zinc oxid in the charge, whether it is present naturally in the ore or is formed as the result of artial roasting of the sulfid, will not inte ere'with the practice of my invention.

The production of carbon bisulfid, which has considerable commercial value, is a feature of my processand'may bean im ortant feature when the ore to be treated is 'gh in sulfur. If desired, the carbon bisulfid may be put to'immediate use to furnish the 'motive ower for driving a gas-engine, which may e coupled with a dynamo furnishing current for the reduction process. In some cases, however, the carbon bisulfid produced can be commerciall neglected, the profit being derived wholly om the'metals recovered.

In the case of zinc ores the zinc is reduced in the form of vapor and may be collected in li uid form.

any well-known way. It may be burned to produce zinc-white; but preferabl it is condensed and 'drawn from the rect current is used and t e roduction' of carbon bisulfid can be confine to the neighborhood of one of the electrodes, the zincva or liberated near the other electrode can be ept substantially undiluted. In this conv nection, however, it should be noted that in the reduction of the zinc from sulfid ores to produce "carbon'bis'ulfid. the proportionof zinc-vapor relative to that of the other gas is trated one form of apparatus con enser in a' the siasio very much higher than when oxid ores are reduced and carbon monoxid produced. This is due to the fact that the roduction of a given volume of carbon bisu fid involves the reduction of approximately twice the quantity of ore which is reduced in producing the same volume of carbon monoxrd.

. In the accompanying drawin s I have illusinvention may be practiced.

y which my Figure l is a plan view of the furnace. Fig.

2 is a longitu inal sectional view thereof, showing also in diagram the electrical connections and an a paratus for utilizing the energy of'the car on bisulfid. Fig. 3 is a cross-sectional view on line 3 3 of Fig. 2. Fig. 4 is a cross-sectional View on line 4 4 of Fig. 2. 5 is a cross-sectional view on line 5 5 of The sameletters of reference-designate the same parts wherever they are shown.

The furnace A shown in the drawin s is of a type adapted for the passage of e ectric current directly through a bath of fused material, such as slag, to produce an electrolytic decomposition of the ore whichmay be dissolved in said bath and also to produce a high de ree of heat throughout the furnace; The wal s B B, of refractory material, may be as thick as desired to withstand corrosion by the slag.- The furnace is divided by a waterjack'eted partition G into two chambers D and E, in one of'which. the ore is reduced, while the other serves as a condensingchamber for the zinc-vapor. 1 The reducing-chamber D is further dividedby a water-'acketed partition G, extending downwardly om the roof of the chamber to a point below the surface of the molten material contained in said chamber. The electrodes vby which current is conveyed to the slag-bath being located one on each side of said partition G, itwill be i seen that gases liberated at one electrode are thereby prevented from mingling withthe gases liberated at the other e ectrode.

materials which are to make up the furnace char e, said-materials bein introduced into rnace by feeders M, and L, which consist of tubes containin said materials, each tube having a rotatab e worm or screw The, electrodes may be formed by bodies of the for advancing the -ma terial through the tube. Thus the feeder J is intended to sup-v ply carbon in the form of crushed coke to the interior of the furnace and forms the anode of the furnace, while the zinc-sulfid ore to. be treated, preferably mixed with crushed coke, is-suppliedby the feeders M and N to form cathode-terminals of the furnace. The electrodes formed by the zinc sulfids may be supplemented by extensions of electrodes M N of solid carbon extending down well into the bath of molten materials. In the diagram, Fig. 2, a dynamo O is illustrated for supplying electric current to.

the furnace, one terminal of said dynamo begine P, which is supp ied through pipe Q with carbon bisulfid gas for its operation from the chamber of the furnace. It is understood, of course, that the electric current may be furnished from any suitable source instead of in the manner indicated.

The furnace is provided with suitable taps for removing the various products of reduction. In the drawings openings Z Z are shown near the top of the chamber D for removing any accretions which may be formed at the surface'ofthe bath of molten mineral, and near the bottom of said chamber P taps V and Ware provided for removing the heavier materials, such as molten lead, which may settle out below the slag. So the zinccondensing chamber E is shown to be provided with a tap-hole T, throu h which the molten zinc may be removed om time to time, and tap-holes X and Y are also r0- vided near the bottom of said chamber for removing the heavier impurities which may settle out from the molten zinc. In case. the

ore under treatment contains lead, for example, in addition to zinc, some of the lead may be volatilized and carried over with the zinc to the condensing-chamber E. This lead will settle at the bottomrof the chamber and may be removed at the taps X and Y.

feeder J bein'g likewise su plied witha quan- .feeders WlllGh serve as electrodes.

tity of crushed coke, t e electric current from generator 0 is assed through the molten slag F by way 0 the material 1n said The current should be sufficient to maintain a tempera'ture in the slag well above the volatilization-point of zincthat is to say, a tem erature from 1,000 to 1,200 centigra e or more. Under these conditions the materials of the charge will be reduced, metallic zinc being liberated in the form of vapor, which will ass over the top of artition G into the con enslng-chamber, Whl e thesulfur unites .I-with the carbon to form carbon bisulfid,

which is conveyed b pipe Q to furnish power for the en ine P. he condensing-chamber E being '0 ose to the reducing-chamber and inclosed by the same furnace-walls will be maintained at a high temperature, so that under otherwise favorable conditions the zinc-vapor may be condensed-in liquid form and drawn ofi at the tap T. Any leadwhich' is present is also reduced in thesmeltin and co lects at the bottom of the chamber under' the slag-bath, where it may be tapped off at V and W. If lead-vapor is carriedover with the zinc into the chamber E it will also be condensed and will settle at the bottom of said chamber, where it may be tapped off at X and Y. The slag which .is formed as the result of smelting adds to the molten bath F, the excess being removed'from time to time atZandZp It will be a parent that myinvention may be practiced by means of apparatus differing widely from the specific form which is here shown for purposes of illustration.

I claim j r 1. The herein-described process of treating sulfid ore whichconsists in dissolving the same in a. fused-mineral bath, and subjecting the.

mixture to the action of an electric current in the presence of carbon, at ahi h'temperature, the sulfid being broken down, t .e metal thereof liberated and carbon bisulfid formed at the same time by the reaction of the sulfur and carbon. V

2. The process of treating zinc ore containing sulfur which consists in mixing said ore with carbon and with slag-forming materials and smelting the mixtui e upon a bath of molten slag in the absence ofair by electrically maintaining in the slag a temperature abovev the volatilization-point of zinc, thereby producing zinc-vapor and a sulfur-bearing compound.

3. The process of treating sulfid ore, which consists in smelting said ore with crushed carbon and slag-forming materials u on a slag-bath in a furnace in which heat 1s de-- veloped internally by the assage of an elec-v tric current, thereby brea ing down the sulfid, liberating the metal and forming carbon bisulfid by the reaction of the carbonand sulfur.

4. .The process of treating zinc-sulfid ore which consists in feeding said ore in contact with a bath ofmolten slag in an electric fur- 'IIO nace from which air is excluded, and there reducing said ore. with carbon and slag-formthrough said slag sufficient to maintain a temperature above the volatilization-point of zinc, thereby liberating. the zinc as metallic vapor and at-the same time forming carbon bisulfid by the reaction of the sulfur and carbon, condensing and collecting the zinc-vapor ing materials, by passingan electric current and isolating and collecting the carbon bi- 5. The process of treatin zinc-sulfid ore zinc, in an electric furnace from which air is excluded, thereby liberating the zinc as metallic vapor and forming carbon bisulfid by the reaction of the sulfur With the carbon. condensing and collecting the zinc-vapor and I isolatingand collecting the carbon bisulfid.

Y 6. The process of treating zinc-sulfid ore which consists in feeding said ore into contact with a bath of molten slag in an electric furnace, and there 'educing said ore with carbon and slag-forming materials, by passing an electric current through said slag sufficient to maintain a temperature above the volatilization-point of mm, thereby liberating the zinc and at thesame time forming carbon bisulfid by the reaction of the sulfur and car- .bon.

7. The process of treating ,zinc sulfids,

' which consists in electrolyzing said sulfid in a fused mineral electrolyte, thereby liberatin v zinc at one electrode and sulfur at a secon electrode, said second electrode being formed of carbon, whereby sulfur combines with the carbon of the electrode to form carbon bisulfid, and separately collecting said zinc and said carbon bisulfid in the absence of air.

8. The process of treating zinc sulfid, which conslsts in electrolyzing said zinc sulfid in a fused mineral electrolyte at a temperature such that volatile zinc is liberated at one electrode and sulfur is liberated at a second electrode, the second electrode bein formed ofcarbon, whereby the carbon and liberated sulfur combine to form carbon bisulfid, and collecting Without intermingling the liberated zinc and the carbon bisulfid.

9. The process of treating zinc sulfid,

' which consists in treatingsaid zinc sulfid with a fused mineral electrolyte in the presence of carbon, by the passage of an electric current,

1 thereby producing a temperature such that volatile zinc and sulfur are liberated, whereby the carbon and liberated sulfur combine to form carbon bisulfid, collecting the liberated zinc and carbon bisulfid, conveying said liberated carbon bisulfid .to' an engine and there liberated zinc and carbon bisulfid, t

emit

sulfid, collecting Without intermingling the ereafter condensing the collected volatile zinc, conveying said liberated carbon bisulfid to an engine, there combining said carbon bisulfid with oxygen to develop mechanical power and causing said power to drive an electric generator sup lying current for said electrolysis.

11. The process of electrolyzing' fused zinc sulfid at a temperature such that volatile zinc is liberated at oneelectrode and sulfur is liberated at a second electrode, said second electrode being formed of carbon, whereby the carbon and liberated sulfur combine to form carbon bisulfid, and collecting without intermingling the liberated zinc and carbon bisulfid. r

12. The process of electrol zing fused zinc sulfid at a temperature such that volatile zinc is liberated at oneelectrode and sulfur is liberated at a second electrode, thesecondelectrode bein formed of carbon, whereby the carbon an liberated sulfurcombine to form carbon bisulfid, collecting without intermingling the liberated zinc and the ,carbon bisulfid, thereafter condensing the collected volatile zinc, conveying said liberated carbon bisulfid to an engine, and there combining said carbon bisulfid with oxygen to de velop mechanical power.

In Witness whereof I hereunto subscribe my namethis 21st day of June, A. D. 1905.

" FREDERICKT. SNYDER. Witnessesr Y 7 DE Wrr'r C. TANNER IRVING MACDONALD. 

